Error handling mode of golang function

Common patterns for handling function errors in Go are: Return error: The function returns an error value, which is nil on success and error type on failure. Global variables: Use global variables to store error values ​​so that functions can easily access and use the error values. Panic: Used when the error is so serious that the function cannot continue to run. The function is terminated immediately and the error is propagated to the caller. Delay: Use the defer statement to execute code before the function returns, suitable for delaying cleanup operations or error handling until the end of the function.

Function Error Handling Patterns in Go

Handling function errors in Go is critical to building robust and reliable applications. There are several common patterns for handling errors, each with its own unique advantages and disadvantages.

1. Returning an error

The simplest way is to let the function return an error value. If the operation is successful, the function returns nil, otherwise it returns a type representing the error, such as error or a custom error type.

func divide(x, y int) (int, error) {
    if y == 0 {
        return 0, fmt.Errorf("cannot divide by zero")
    }
    return x / y, nil
}

2. Global variables

This method uses global variables to store error values. The benefit of this is that functions can easily access and use error values, even if they are called by other functions.

var err error

func init() {
    // 初始化 err 变量
}

func calculate() {
    // ...
    err = fmt.Errorf("an error occurred")
}

func handleError() {
    if err != nil {
        // 处理错误
    }
}

3. Panic

In some cases, when the error is serious enough that the function cannot continue to run, panic can be used. Panic immediately terminates the function and propagates its error to the caller.

func someFunction() {
    // ...
    if err != nil {
        panic(err)
    }
}

4. Delay The

defer statement executes code before the function returns. This allows execution when cleanup operations or error handling are deferred to the end of the function.

func readFile() (string, error) {
    defer file.Close()

    // ...
}

Practical case: file reading and writing

import (
    "fmt"
    "io"
    "os"
)

func readFile(path string) ([]byte, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, fmt.Errorf("open file: %w", err)
    }

    // 使用 defer 语句延迟关闭文件，确保在函数返回之前关闭
    defer file.Close()

    // ... 读取文件内容

    return data, nil
}

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